Two explosions rocked the Algerian capital on Tuesday, public radio said. One explosion tore through a school bus in front of the supreme court in Algiers while a second blast occurred near a police station in the residential district of Hydra.

Public radio, Algiers Network 3, said the bombs went off about 10 minutes apart.

Algerian Interior Minister Noureddine Yazid Zerhouni said the blasts were caused by car bombs. The attacks targeted the headquarters of the Constitutional Council and the UN High Commission for Refugees, Zerhouni told the national radio channel III. A U.N. spokesman said one employee of the U.N. refugee agency was killed and another was missing.

U.N. Secretary-General Ban Ki-moon strongly condemned the bombings. "This is just unacceptable," said Ban, according to the AP. "I would like to condemn it in the strongest terms. It cannot be justified in any circumstances."

"An attack like this is among the easiest actions to carry out. I have always said that we are not safe from these sorts of attacks," Zerhouni told reporters in remarks carried by the official APS news agency. "Everything depends on the degree of our vigilance and our degree of mobilization against this. You will have noticed that there are fewer and fewer attacks of this nature. That means that the groups carrying out these sorts of attacks are facing more and more problems."